CHAPTER 7. TESTING FOR CONCUSSION
damage to axons – the main
shafts of neurons – caused by
the shear forces associated
with a knock to the head or
whiplash movement.
Professor Henrik Zetterberg,
a neurochemist from the
University of Gothenburg in
Sweden, has been looking at
indicators of axon damage that
might meet the criteria of a
marker for more subtle brain
damage. He says that, so far,
research has singled out two
key candidates. The first, the
protein tau, is already making
a name for itself as a biological
villain of other conditions
such as Alzheimer’s disease.
Research has shown that
amateur boxers have higher
levels of tau in the blood
stream the week or so after
a bout, even if they’re not
knocked out. These levels
then slowly return to normal
around eight to 10 weeks
after the impact, as long as the
boxer doesn’t have any more
head impacts during that time.
Similarly, a study by
Zetterberg and his colleagues,
conducted among Swedish
ice-hockey players, showed
that tau levels were
elevated in the blood after a
concussion when compared
to measurements taken
at the start of the hockey
season. They also found
the levels of the protein
S-100B increased following
a concussion, although
not nearly as much as tau
increased.
Research has also found a
correlation between blood
tau levels and the severity
of a TBI, where levels were
higher in patients with a
poorer outcome following
injury. These studies suggest
the potential for tau to be
used as a diagnostic indicator
for concussion.
Another promising
biomarker candidate for
concussion is neurofilament
light protein. Like tau, this
is also a marker of damage
to axons. Levels seem to
peak four to 10 days after
Australia has a strong sporting culture. We love our sport: we watch our kids grow up playing
it on the weekends, and our professional athletes are household names. The nature of contact
sports means that head knocks are sometimes unavoidable. But changing the fundamental
rules of these sports isn’t the only way to make them safer. Through research, we can improve
the diagnosis and management of concussive episodes. Finding a suitable biomarker to test
for concussion will enable rapid diagnosis and reduce the risk of repeated head injury. And
imaging technology is helping us understand how concussion affects the brain. Longitudinal
studies to track brain changes have never been undertaken before, and are the missing piece
of the concussion puzzle. In the long-term, they are critical to
understanding the lasting consequences of head injury, and
will enable us to intervene early and prevent or reduce lasting
damage. Through research, we can begin to tackle some of
concussion’s unanswered questions.
the injury, but unlike tau,
neurofilament light protein
levels are raised in the
cerebrospinal fluid. This
liquid cushions the brain and
spine, and samples can only
be taken in a sterile hospital
setting. The challenge now
for researchers is to refine
the tests for these biomarkers
and use them in combination
with imaging techniques
in order to better diagnose
concussion and assess when
it is safe to return to play.
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